StackBlitz + Github + Angular

For example you have any github repo with Angular in it
https://github.com/angular-university/rxjs-course/
You can execute this repo by accessing it via stackblitz like this:
https://stackblitz.com/github/angular-university/rxjs-course/
It gives you file browser. All your changes reflect automatically.
This trick works with branches and commits too:
https://stackblitz.com/github/{GH_USERNAME}/{REPO_NAME}/tree/{TAG|BRANCH|COMMIT}

Angular Service - is a singleton object that gets instantiated only once during the lifetime of the application. Angular services contain methods that maintain the data throughout the life of the application. The main intent of the Angular services is organise and share business logic, models or data and functions with various components of the application.